The present invention relates to combining of images and to controlling a cursor when images are combined.
Some computer systems combine images. An example is a computer-based video conferencing system 110.1 shown in FIG. 1. System 110. 1 is of type VMU-1000 (Trademark) available from Sony Electronics Inc. of San Jose, Calif. System 110.1 allows human user 120.1 to conduct a video conference with two other users shown at 120.2. Users 120.2 use video conferencing system 110.2 which may be identical to or different from the system 110.1.
User 120.1 controls the system 110.1 with a mouse 130 connected to computer 140. Computer 140 executes a video conferencing software application 150. Under the control of this application, the computer exchanges control signals with video overlay system 160 over a link 170. Video overlay system 160 also receives from computer 140 an analog signal CV for display on monitor 174. The analog signal incorporates a window 178VC generated by application 150. Window 178VC includes a menu of choices for user 120.1. The signal CV also incorporates a window 178A generated by some other application (not shown) executed by computer 140, for example, a spreadsheet.
Video overlay system 160 also receives a remote video (xe2x80x9cfar-side videoxe2x80x9d) signal FV from system 110.2 over a telephone link 182. (In addition, system 110.1 receives an audio signal from system 110.2. The audio signal is demultiplexed and processed by another portion (not shown) of system 110.1.)
The video signal FV incorporates an image displayed in window 178F on monitor 174.
Video overlay system 160 receives a local video (xe2x80x9cnear-side videoxe2x80x9d) signal NV from camera 186 which is part of system 110.1. Video overlay system 160 sends the near-side video to system 110.2 over telephone link 182. (The local audio is sent out over the same link.)
If desired, the local video image carried by signal NV is displayed on monitor 174 in window 178N.
FIG. 2 illustrates a portion of video overlay system 160. Motion video block 210 receives far-side and near-side signals FV, NV (xe2x80x9cmotion video signalsxe2x80x9d) and generates an analog signal MV incorporating the far-side and near-side images. Video switch 220 selects either the signal MV or the computer video signal CV. The output of video switch 220 controls an electron beam (not shown) in CRT monitor 174. When the beam traces the monitor screen areas in which the computer video is to be displayed (computer video is the image generated by computer 140, including the windows 178VC, 178A in FIG. 1), the switch 220 selects the signal CV. When the F g beam traces the areas in which the motion video is to be displayed (the motion video includes the far-side and near-side images in windows 178F, 178N), the switch selects the motion video signal MV.
Video switch 220 is controlled by select signal ALPHA generated by multiplexor control mask 230. Multiplexor control mask 230 includes a memory (not shown) storing a 1 or a 0 for each group of pixels in monitor 174. These 0""s and 1""s are read out of the memory to generate the select signal ALPHA. See PCT application WO 97/50242 xe2x80x9cSystem and Method for Overlay of a Motion Video Signal on an Analog Video Signalxe2x80x9d published Dec. 31, 1997.
The signal CV incorporates cursor 240 (FIG. 1). The cursor is generated by computer 140 in response to signals from mouse 130. The cursor helps the user 120.1 to control the system 110.1.
It is desirable to make the cursor more convenient to use.
The inventor has observed that when the mouse moves the cursor into the motion video, the cursor disappears and the user becomes disoriented. The cursor disappears because the motion video is constructed from the signal MV and the signal MV does not incorporate the cursor.
In some embodiments of the present invention, the cursor is incorporated into the motion video. In some embodiments, the motion video signal MV is combined with the computer video signal CV. For example, in some embodiments, MV is summed with CV, and the motion video is constructed using the sum signal. Therefore, if the mouse moves the cursor into the motion video, the cursor is displayed in the motion video.
In some embodiments, when MV carries the motion video, the signal CV=0 (CV is black for RGB embodiments) except for the cursor. Therefore, the motion video is not degraded.
The present invention is not limited to video conferencing or to motion video. Some embodiments combine non-video-conferencing signals that incorporate images. One or more of these signals are generated by a system capable to incorporate a cursor into an image. At least a portion of the cursor can be combined with another image.
Other features and advantages of the invention are described below. The invention is defined by the appended claims.